Chester e



. nitro-cymene in an zidin is first UNITED STATES PATENT OFFICE.

CHESTER E. ANDREWS, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE SELDEN COMPANY, OF PITTSBURGH,

PENNSYLVANIA, A CORPORATION OF DELAWARE.

DIMETHYL-DIISOPBOIYL-ZBENZIDIN AZO DYESTUFFS AND PROCESS OF MAKING SAME.

1,314,925. No Drawing. 4

To all whom it may concern:

Be it known that I, CHESTER E. ANDREWS, a citizen of the United States, residing at Pittsburgh, in the county of Alleghen and State of Pennsylvania, have invente certain new and useful Improvements in Dimethyl Diisopropyl Benzidin Azo Dyestuffs and Processes of Making Same, of which the following is a specification.

The present invention relates to azo roduced from din, by coupling with a suitable amino aromatic body, or a derivative of such an aromatic body, and to the process of producing such dyes.

Dimethyl-diisopropyl-benzidin may conveniently be prepared by reducing monoalkaline solution, by

means of powdered zinc to produce hydrazo-cymene, and then subjecting the lat dyes ter to the benzidin reaction. Such a process and the product thereof are claimed in my copending application 191,605, filed September 15, 1917.

The process of the present invention is elfected in a general way, by the following series of steps. Dimethyl-diisopropyl-bentetrazotized and the product then coupled with the amino body in an acid solution, while maintained at a temperature of 10 C. or below. This last mentioned reaction is likely to be rather slow, requiring in some instances one day and in some instances longer or' shorter periods oftime, depending upon the relative degree of activity of the amino body employe temperature, purity and other factors.

As a specific example of the process, the following is given: 29 parts 0 dimethyldiisopropyl-benzidin are dissolved in about 300 parts of hot water containing 24 parts of hydrochloric acid (gravity 1.2) and the to about 10 C.

' While maintained at this temperature a furof 36 parts of hydrochloric ther uantity and about 14.4

acid gravity 1.2) is added,

Specification of Letters Patent.

parts of sodium nitrite, previously dimethyl-diisopropyl-benziis a brown powder,

Patented Sept. 2, 1919.

Application filed September 19, 1917. Serial No. 192,212.

dissolved in a small amount of water, is a ded. This produces the tetrazo derivative.

The tetrazo derivative is added to a cold solution of about 54 parts of sodium naphthionate and 100 parts of water, the mixture stirred mechanically for two or more days. After first one-half of stirring, a solution of 35 parts of sodium carbonate is added, a few drops at a time, so that the whole has been introduced at the end of two days. On the next day the mixture is heated to 80 C. and a little salt is added, so that the solution remains only slightly yellow. The precipitated color is filtered, dried and ground. It soluble in water with brownish red color and dyes cotton direct from an alkaline bath.

Instead of sodium naphthionate referred to in the above example, various other amino bodies can be employed, such as mono amino cymene, anilin, alpha or beta naphthyl-amin, x lidenes, toluidins, dimethyl anilin, meta p enylene diamin or the sulfonic acids 0 the above mentioned substances, and the derivatives of these sulfonic acids, such as sulfanilic acid, -acid 1:8-amino-naphthol- 3:6. disulfonic acid), -acid (1:8 aminonaphtholl: 6 disulfonic acid), RR-acid (2 :8-amino-naphthol-3 i6 disulfonic acid) 1- amino 8 naphthol 3 5 disulfonic acid, 2- napthylamin-6-sulfonic acid, 2-naphthylamin-'l-sulfonic and various others. In general the sulfonic acids produce water-soluble dyestuffs, but in the case of the simple amins .the dyestuffs may or may not be water-soluble.

In the present invention instead of using a sin le amino aromatic body, a mixture of such odies can be employe or preferably one amino body can be combined at one en of the dimethyl-diisopropyl-benzidin structure, and subsequently another amino body (or under some ci cumstances other materials, such as a hydroxy aromatic body) coupled at the'other end of'the structure. The

each of which components at least-one N Hg.

'in which each of reactions taking placein the process of the thionate as the specific example may be illuspresent invention, employing sodium naphtrated convemently as follows:

5 I i' w sh CHI GH(CHa):

I 0 Na. (Two molecules of hydrochloric acid are produced and liberated by this reaction).

What I claim is: 1. The herein described new dyestufl's consisting of the tetrazo compound of dimethyloaN a diisopropyl-benzidin coupled with an amino aromatic compound, said dyes being capable of dyeing fabric in an alkaline bath.

2. The herein described new dyestuffs having the general formula 011mm): i l;

in which each of the components X con-' 3. The herein described new dyestufl's havsists of a plurality of benzene nuclei, and in ing the general formula group is substitute CHESTER E. ANDREWS.

the components X consists of an aromatic residue containing an HSO group and an NH -group,

4. A dyestufl' consisting of the tetrazo compound of dimethyl-diisopropyl-benzidin 

